In order to improve voltage conversion ratio of a circuit, usually a DC-DC converter selects a duty cycle with an extreme value or introduces a transformer structure. In addition, changing circuit topology structure has also been tried in order to improve the voltage conversion ratio of the circuit. However, voltage gain achieved by the foresaid methods is still limited strictly by the circuit topology structure and the duty cycle value.
Therefore, there is a need for a new circuit structure capable of increasing the voltage gain.